Nitrogen Effects on Optical and Electrical Properties of Amorphous Carbon

Abstract

Optical and electrical properties amorphous carbon nitride (a-CN) has been investigated on films deposited by reactive R.F. sputtering source with a graphite target. The amorphous carbon nitride samples were prepared under a gas mixture of nitrogen (N2) and /or Argon (Ar).The optical transitions are governed by the  and * electronic state distributions, related to sp2- and sp1-hybridized C and N atoms. Specific lonepair electronic states arise from groups (CN) with sp1-hybridized C atoms, which may form C≡N triple bonds or —N=C=N— longer chains. Photoluminescence spectra show a maximum around 650 nm. Two conduction regimes at high and low temperature are found in a-CN samples. The corresponding activation energies decrease with the increase of target voltage.